Coking-retort oven



July 23, 1929. .1. BECKER 332L763 GOKING RETORT OVEN Filed Oct. 13. 1922 5 Sheets-Sheet l g Zz 06/2 i074 v July 23, 1929. J. BECKER COKING RETORT OVEN Filed Oct. 13. 1922 5 Sheets-Sheet 2 fi ll 5 Sheets-Sheet 4 J BECKER COKING RETORT OVEN July 23, E929.

July 23, 1929. J. BECKER COKING RETORT OVEN Filed Oct. 15, 1922 5 Sheets-Sheet 5 I I l mum I H M NH HUNNNIH HHHHHHH MMHH I (l ll Patented July 23, 1929.

UNITED, STATES JOSEPH BECKER, or 'rrr'rsnunon, PENNSYLVANIA, ASSIGNOR r0 THE KOPPEBS com PATENT- OFFICE,

PANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.-

COKING-RETORT OVEN.

Application filed October 13, 1922. Serial No. 594,376.

This invention comprehends improve ments of general utility in the coking oven retort art; and also comprehends certain improvements especially applicable to coking retort ovens of the well known cross-regen erative type exemplified in the patent to H. Koppel-s, No. 818,033, dated April 17, 1906, and my prior Patent No. 1,374,546, dated April 12, 1921.

The invention has for objects the provision of a coking retort oven having as important characteristics: A sole channel construction permitting the entire series of inflow op erating regenerators on both sides of the longitudinal central plane of the battery to receive the inflow entirely from one side of the battery, while concurrently the outflow from the entire series of outflow operating regenerators located on both sides of said central plane passes out throughflow control devices located on the opposite side of the battery; and, as features that may be secured by the above structural improvements, a substantial reduction in the number of parts and mechanism heretofore required for operating a cross-regenerative coke oven having regenerators disposed in series along the opposite sides of the battery in accordance with the cross-over principle exemplified in my prior Patent No. 1,374,546, and the elimination of supplemental mains and other parts, when burning in the flues of the battery coke oven gas in an atmosphere diluted with return waste gas.

In addition to the objects recited above, the invention has for other objects such other improvements or advantages in construction and operation as are found to obtain in the structures and devices hereinafter described or claimed.

In the accompanying drawings, forming a part of this specification, and showing for purposes 01 exemplification, a preferred form and-manner in which the invention may be embodied and practiced, but without limiting the claimed invention to such illustrative instance or instances:

Figure 1 is a crosswise vertical section through a coke oven battery embodying features above specified and equipped with the improvements of the present invention, the view being taken longitudinally through a heating wall and a pair of communicably connected regenerators;

Figure 2 is another crosswise vertical section taken along the major axis of a coking chamber;

Figure 3 is a composite vertical sectional elevation taken longtiudinallyof a coke oven battery in planes indicated by the lines A A.,

BB, C-C of Figure 2;

Figure 4 is a horizontal section through the regenerators' taken in a plane indicated by the line E-E of Figures 2 and 3; and

Figure 5 is another horizontal section through the regenerators but on a reduced scale and showing in plan the waste gas tunnel or stack flue connections with the regenerators.

In the embodiment illustrated in the drawings, the invention is incorporated in a coke oven battery having provision for being operated either with coke oven gas burned in an atmosphere of ordinary preheated air, such as is utilized in ordinarycoke ovens, or with coke oven gas burned in an atmosphere containing both air and a neutral gaseous diluent which is introduced into the flame fines separately from the air. For convenience, the present description will be confined to the present illustrated embodiment of the invention in such an oven battery; the novel features and improvements made by the invention, are susceptible of other applications, such, for example, as ordinary so-called coke ovens employing coke oven gas as a fuel, or ordinary so-called gas ovens employing producer gas as a fuel; hence, the scope of the invention is not confined to the specific use and specific embodiment herein described as an illustrative example.

' Referring to the drawings there are illustrated views of a'coke oven battery or plant of the by-product type, having features above specified; said oven battery embodies in its construction a plurality of crosswise elongated heating walls 11, 11 and a plurality of intermediate crosswise elongated vertical coking chambers 12, 12. The heating walls 11 form the side walls of the respective coking chambers 12, as shown more particularly in Fig. 2, and, in the present instance, are directly supported by the heavy supporting or and are themselves supported upon a flat mat or platform which constitutes the sub-foundation on which the entire battery rests.

The coal to be coked is charged into the several coking chambers or ovens throu h charging holes 14 located in the top 15 of t e oven battery and positioned directly above the oven or chambers 12, as shown in Figs. 2 and 3. These charging holes 14 are equipped with the usual removable covers, which are removed during charging of the individual ovens or coking chambers and are placed in position to close the tops of such coking chambers during the entire coking or distilling operation. The gases of distillation pass from the tops of the several coking chambers 12 through gas outlets 16 and thence through ascension pipes (not shown) into the usual as collecting main which carries the distillation products to the by-product recovery apparatus.

Heat for coking the charges of coal in the several ovens or chambers 12 is derived from the heating walls 11, which, as above mentioned, extend crosswise of the battery at the sides of the coking chambers. Referring now more particularly to Figs. 1 and 3, each heating wall 11 is constituted of a plurality of flame or combustion flues 17. The flame flues of each heating wall are, in accordance with the invention, operatively disposed into a single group, that is to say all of the flues of each heating wall operate concurrently as upflow or downflow flues, as will be hereinafter more fully explained. When the flame flues on one side of a coking chamber are burning, that is to say, operating for upflow, the flame flues on the opposite side of the same coking chamber are operating for downflow to permit exhaust of the waste gases. Consequently heating is maintained continuously from end to end on one side of a charge of coking coal in each coking chamber,the heatbeing applied to the fulllength of one side of such charge during an entire period and, then, after reversal, being applied to the full length of the opposite side of the charge, until a subsequent reversal is effected.

The crosswise regenerators 18 of the retort oven or battery are located at a lower level than the aforesaid heatin walls 11 and coking chambers 12, and, in t e present instance, extend in parallelism between the pillar walls 13. Located in the middle lengthwise vertical plane of the coke oven battery, is a vertical partition 19, as shown in Fig. 1, which partition extends from the mat of the. battery nearly 'to the bottom of the overlying coking chamber and from one to the other of the pillar walls 13, and the other walls which are between the pillar walls; the small spaces provided at the tops of partitions 19 permitting equalization of pressure in the respective regenerator 'chambers F and G on opposite sides of the partitions. The regenerators,

which are respectively located on opposite sides of the battery extend inwardly to said partition 19 and are separated thereby as clearly shown in Fig. 1. Each regenerator 18 is a chamber containing open brick work, commonly called checker work, and indicated at 20, with distributing sole channels 21 underneath such checker work, the'channels forming the soles of such chambers and opening up into the checker work.

The regenerators are heated, in alteration, by the hot combustion products that draw oil from the flame or combustion flues hereinbe fore mentioned and then impart such heat to the medium thatthey feed into these flame flues. For convenience, the several regenerators located on one-side of the battery and which respectively communicate with groups, F of the combustion flues may be generally designated by the reference character F, and those regenerators which are located on the other side of the battery and which respectively communicate with groups G of the combust1on.flues may be designated generally by the reference character G. The regenerators are furthermore grouped into alternate pairs K and intermediate pairs L, each pair K or L comprising a regenerator F and a regenerator G on the opposite side of the central longitudinal partition 19.

Each regenerator is provided with a series of ducts 23 all of which lead respectively to individual flame flues 17 of the same heating wall. The regenerators G are communicably connected with the flues of the same heating walls as the corresponding regenerators F of the crosswise pairs. With this construction, each heating wall is communicably connected with two regenerators, one located on.

one side of the battery and the other regenerator on the other side.

In the present embodiment of the invention, the entire series of flame flues 17 of each heating wall 11 is either burning or operating for downflow to convey waste products to the regenerators beneath and consequently the alternate regenerators K, or intermediate regenerators L alined on opposite sides of the central longitudinal partition 19 operate concurrently for flow in the same direction and in the same manner. The reversal in flow through the flame flues 17 on opposite sides of a coking chamber,-and their communicably connected regenerators may thus be said to take place longitudinally of the oven battery, instead of transversely thereof, as has heretofore been a common practice in this art. The

reversal of the oven is effected at the end of an operating period determined by practice, and by means of any preferred t pe of reversing mechanism. The function 0 such reversal is as follows: The regenerators that prior to the reversal operated as inflow regenerators become outflow regenerators, and the outflow operating regenerators become inflow operating regenerators; the upburning series of flue switches function with the downburning series of flues of the next adjacent heating wall, and the supply of gas is turned oil from the previously upburning flues and turned on into the mains of the previously downburning flues. 7

Each flame flue 17 of each heating wall has at its top a port or opening 24 for draft and the passage of combustion products or waste gas from the flame within the flue. These ports 24 open up into horizontal or bus flues 25 formed in the heating walls and connecting all of the vertical flues that communicate with such horizontal flues 25 by means of the ports 24. According to the invention, there are in each heating wall a plurality, in the present instance, two of such horizontal flues 25 positioned end to end with respect to each other and respectively located on opposite sides of the partition 19. By reason of the fact that there is a plurality of such horizontal flues 25, these flues 25 are not required to be of so great capacity as that necessary in present practice and consequently the cross sectional area of each horizontal flue 25 may be materially reduced proportionately with v the length of such flue, with the result that the thickness and strength of-the heating walls are substantially increased in the region of the horizontal flues. Moreover, because of the fact that each horizontal flue 25 communicates with a substantially reduced number of vertical flues, in the present instance, half of the flues of a heating wall, uniformity in distribution of the flow through the vertical fines and the communicating regenerators is greatly promoted.

As shown, the two horizontal flues 25 of each heating wall are communicably connected respectively by means of passageways or crossover ducts 26 with the corresponding horizontal flues of one of the next adjacent heating walls. Thus, the entire flow from a heating wall, within the flues of which combustion is being maintained, passes through and downwardly through all of the flues of the next adjacent heating wall and each reversal operation is accompanied by a reversal in direction of the fiow of all of the flues of each heating wall.

The draft through the ports 24 may be regulated by means of the usual movable dampers or sliding bricks'27, positioned in the ordinary way in the bottoms of the horizontal flues 25 and adapted to be reached by access flues 28 which extend from the top of the horizontal flues 25 in each heating Wall to the top 15 of the battery, there being an access flue positioned over each flame or combustion flue of each heating wall.

Extending crosswise of the battery in each pillar wall 13 and located beneath the heating wall 11 there-above, is a pair of gas-supply channels 29 and 30.- These channels 29 and 30 are for the purpose of supplying coke oven gas to the several flame flues on each side of the central line L, and to accomplish this end, the channel 29 communicates with the individual flues 17 on the near side of said line L by means of ducts 31 that lead from such channel 29 individually into the bottoms of individual flues; and the channel 30 which supplies the several flues that are located on the far side of the aforementioned dividing line L communicates therewith by means of 4 similarly connectingducts. Within the several ducts are disposed theusual nozzles 32. The supply of coke oven gas to the respective channels 29 and 30 is derived from coke oven gas mains of the usual type and respectively located on the opposite sides of the battery and extending longitudinally therealong. Suitable means is provided for admitting or cutting off the supply of gas with respect to each pair of channels 29 and 30, it being understood that the gas supply is either concurrently maintained or concurrently shut off from both channels of each pair,

According to the invention there is provided along each side of the battery a waste gas tunnel 33, the waste gas tunnel corresponding to the alternate pairs K of the generators being designated K and the waste gas tunnel correspondin to the intermediate pairs L of regenerators eing designated L The two waste tunnels K and L merge into a common waste gas main 34 leading tothe usual stack. A reversing damper 60 is provided in each tunnel K L and the usual reversing mechanism is operated at the end of each operating interval to open the damper 60 of a tunnel K or L to place such tunnel in communication with the stack, while concurrently closing the damper of the other waste gas tunnel to shut it ofl from the stack. A port 61 in the waste gas tunnel K is communicably connected by any suitable valve controlled pipe 70 with a similar port 62 in the other waste gas tunnel L Any conventional form of reversible flow producing device 71 may be employed in the pipe, with control valves 72. This construction permits waste gas to be drawn ofi from a tunnel, that is in communication with the stack and that is receiving the outflow from outflow regenerators, and directed into the other waste gas tunnel for delivery with the air tothe inflow regenerators, whenever it is desired to burn the gas in the inflow operating flues in an atmosphere containing a neutral gaseous diluent.

The sole channels 21 of theregencrators G of the alternate pairs K discharge into the waste gas tunnel K although located on the 125 opposite side of the battery from said waste gas tunnel. The sole channels 21 of the regenerators F of the alternate pairs K likewise discharge into the waste gas tunnel K 7 The sole channels 21 of the regenerators F of tors G of said intermediate pairs discharge into the waste gas tunnel L With this construction, the flow through both the alternate and intermediate pairs of regenerators, each alternate or intermediate series of pairs comprising regenerators located on opposite .sides of the battery, is controlled for the entire alternate series of pairs on one side of the battery and for the entire intermediate series of pairs on the other side of the battery. Consequently, whenever the combustion is effected in an atmosphere containing return tors become inflow regenerators.

In operating the battery with coke oven gas in the ordinary manner the mushroom valves of both series K and L are closed.

waste gas or diluent, that waste gas. tunnel Since the valves and.72 in the correspondwhich is cut off from the stack ma ployed as the return waste gas main or delivering the diluent to the inflow regenerators and flues and-the employment of separate waste gas mains with their reversing valve connections is entirely eliminated. The flow through the regenerative sole channel 21 corresponding to each regenerator is controlled by a flow box 35 communicating with said sole channel and with the waste gas tunnel 33 by a-duct 36. Each flow box 35 is provided with an air lid 37 for admitting air to its communicably connected regenerator, when operating for inflow, and with a mushroom valve 38 adapted to beopened to permit the waste gas to flow into the stack, when the regenerator is operating for outflow. The flow boxes corresponding to and cont-rolhng the operation of the alternate pairs K- of crosswise regenerators are designated K and the flow boxes controlling the operation of the intermediate pairs L of crosswise regenerators are designated L. The entire series.-

of flow boxes K control the regenerator flow into or from the waste gas tunnel K and are operated in unison either to connect the pairs K of regenerators with the waste gas tunnel or by closing the mushroom valves to shut ofl? such regenerators from communication with the waste gas tunnel, except when diluent operation is employed, as hereinafter explained. The series of flow boxes L function and operate in a manner similar to the flow boxes K.

For operating the battery with coke oven gas as the fuel, combined with a supply of neutral gaseous diluent to the fines, the mushroom valves are provided with ports 39 (Figure 2) to permit waste gas to pass into the inflow regenerators along with the air which is admitted through the open air lids 37. The ports are designed to admit the proper quantity of waste gas to dilute the air to the extent desired.- During the inflow of air and return waste gas into inflow regenerators, such as the alternate pairs K, gas is being delivered to the flame flues that are comregenerators is passing out through the tunnel L and part of the waste gas from said be em-- iilg tunnel 33 and .pipe respectively, are then closed there will be no tendency of the air to pass through the port 39.- This permits only air to flow into the inflow regenerators.

The invention as hereinabove set forth is embodied in a particular form of construction but maybe variously embodied within the scope of the claims hereinafter made.

I claim: 1; In a coke oven battery, in combination: a plurality of coking chambers; heating walls contiguous to such coking chambers and respectively. constituted of vertical combustion flues; regenerators located at a lower level than the coking chambers and the heating walls, said regenerators being grouped into pairs crosswise of the battery, each pair of such regenerators being communicably connected with combustion flues of a single heating wall; the combustion flues of each heating wall being communicably connected with the combustion flues of an adjacent heating wall; mains respectively located on opposite sides of the'battery and respectively alternatively operable for feeding return waste gas to or discharging waste gas from the regenerators; means for connecting one of said mains with the stack while concurrently shutting off the other; reversing valve connections between alternate pairs of said regenerators and the waste 'gas main on one side of the battery; and reversing valve connections between the intermediate pairs of such regenerators and the waste gas main on the other side of the battery; each reversing valve connection having means, when operated for inflow, to permit waste gas to flow from its corre sponding main into its communicably-connected regenerator; substantially as specifieth 2. In a coke oven battery, in combination: a plurality of coking chambers; heating walls contiguous to such coking chambers and respectivelyconstituted of vertical combustion flues; regenerators located at a lower level than the coking chambers and the heating walls, said regenerators being grouped into pairs crosswise of the battery; mains respectively located on opposite sides of the battery and respectively alternatively operable for feeding return waste gas to or discharging waste gas from the regenerators;

the stack while concurrently shuttin ofi the other; reversing valve connections etween alternate pairs of said regenerators and the waste gas'main on oneside of the battery;

' and reversing valve connections between the 1ntermediate pairs of such regenerators and the waste gas main on the other side of the battery each reversing valve connect1onhaving means, when operated for inflow, to

permit waste gas to flow from its corre-' sponding main into its communicably connected regenerator; substantially as speci- 3. In a coke oven battery, in combination: a plurality of coking chambers; heating walls contiguous to such coking chambers and respectively constituted of vertical com- .bustion flues; regenerators located at a lower level than the coking chambers and the heating walls, said regenerators being grouped into pairs crosswise of the battery; mains respectively located on opposite sides of the battery and respectively alternatively operable for feeding return waste gas to or discharging waste gas from the regenerators; means for connecting one of said mains with the stack while concurrently shut-tin off the other; reversing valve connections etween alternate pairs of said regenerators and the waste gas main on one side of the battery; and reversing valve connections between the intermediate pairs of such re enerators and the waste gas main on the ot er side of the battery; substantially as specified.

4. In a coke oven battery, in combination a plurality of coking chambers; heating walls contiguous to such coking chambers and respectively constituted of vertical combustion flues ;regenerators located at a lower level than the coking chambers and the heating walls, said regenerators being grouped into pairs crosswise of the battery, each pair of such regenerators being communicably connected with combustion flues of a single heating wall; the combustion flues of each heating wall being communicably connected with the combustion flues of an adjacent heating wall; mains respectively located on opposite sides of the batterfy and respectively alternatively operable or feeding return waste gas to or discharging waste gas from the regenerators; means for connecting one of said mains with the stack while concurrently shutting off the other; reversing valve connections between alternate pairs of said regenerators and the waste gas main on one side of the battery; and reversing valve connections between the intermediate and respectively"constituted of vertical conibustion flues; regenerators located at a lower level than the coking chambers and the heating walls, said regenerators being grouped into pairs crosswise of the battery, each pair of such regenerators being communicably conne'ctedwith combustion flues of a single heating wall; the combustion flues of each heating wallbeing'communicably connected with the combustion flues of an adjacent heating wall; mains res ectively' located on o posite sides of the attery; reversing va' ve connections between alternate pairs of said regenerators and the waste gas main on one side of the battery; and reversing valve connections between the intermediate pairs of such regenerators and the waste gas main on the other side of the battery; substantially as specified.

6. In a coke oven battery, in combination:

' a plurality of coking chambers; heating walls contiguous to such coking chambers and respectively constituted of vertical combustion fiues; regenerators located at a lower level than the coking chambers and the heating walls, said regenerators being grouped into pairs crosswise of the battery; waste gas mains respectively located on opposite sides of the battery; reversing valve connections between alternate pairs ofsaid regenerators and the waste gas main on oneside of the battery; and reversing valve connections between the intermediate pairs of such regenerators and the waste gas main on the other side of the battery, each of said connections comprising a separate passageway leading to eachone of a pair of regenerators; substantially as specified.

7. In a coke oven battery, in combination: a plurality of coking chambers; heating walls contiguous to such coking chambers and respectlvely constituted of vertical combustion flues; regenerators located at a lower level than the coking chambers and the heating walls, said regenerators being grouped into pairs crosswise of the battery, each air of such regenerators being communicab y connected with combustion flues of a single heating wall; the combustion flues of each heating wall being communicably connected with the combustion flues of-anadjacent heating wall; mains respectively located on opposite sides of the battery; reversing valve connections between some of the pairs of said regenerators and the waste gas main on one side of the battery; and'reversing valve connections between the-other pairs of such regenerators and the waste gas main on the other side of the battery; substantially as specified. a

8. In a coke oven batter in combination: a plurality of coking cham ers; heating walls contiguous to such coking chambers and respeetively constituted of vertical combustion fines; regenerators located at a lower level walls, said regenerators being grouped into pairs crosswlse of the battery; waste gas mains respectively located on opposite sides of the battery; reversing valve connections between'some of the pairs of said regenerators and the waste gas main on one side of the battery; and reversing valve connect-ions between the other pairs of such regenerators and thewaste gas main on-the other side of the battery, each of said connections comprising a separate passageway leading to each one of a pair of regenerators; substantially as specifie 9. In a coke oven battery having coking chambers, heating walls contiguous to said coking chambers and respectively constituted of vertical combustion flues, the combustion fines of each heating wall being communicably connected with the combustion flues of an adjacent heating wall, the improvement characterized by regenerators grouped in'pairs crosswise of the battery, each pair of such regenerators being communicably connected with combustion flues of a single heating wall, and the sole channels of the alternate pairs of regenerators having their ports on one side of the battery while the sole channels of the intermediate pairs of regenerators have their ports on the opposlte side of the battery; and two series of flow box connections respectively located on opposite sides of the battery and respectively controlling the flow through the sole channel ports of the alternate and intermediate pairs of regenerators; substantially as specified.

10. In a coke oven battery having coking chambers, heating walls contiguous to said coking chambers and respectively constituted of vertical combustion flues, the combustion flues of each heating wall being communicably connected with the combustion fines of an adjacent heating wall, the improvement characterized by regenerators grouped in pairs crosswise of the battery, each pair of such regenerators being communicably connected with combustion flues of a single heating wall, and the sole channels of the alternate pairs of regenerators having thelr ports on one side of the battery while the sole channels of the intermediate pairs of regenerators have their orts on the opposite side of the battery; substantially as specified. I

11. In a coke oven battery having coking chambers, heating walls contiguous to said coking chambers and respectively constituted of vertical combustion fines, the combustion flues of each heating wall being communicably connected with the combustion fines of an adjacent heating wall, the'improvement characterized by regenerators grouped in pairs crosswise of the battery, each pair of such regenerators being communicably connected with combustion flues of a single heating wall, and the sole channels of some of the pairs of regenerators havin their ports on one side of the battery'w ilethe sole channels of the other pairs of regenerators have their orts on the opposite sides of the battery; su stantially as specified.

12. In a coke oven battery having coking chambers, heating walls conti none to' said.

ports only on the opposite .side of the battery; substantially as specified.

13. In an oven battery, a heating wall having combustion flues adapted to all simultaneously pass the gases in the same direction and regenerators arranged end to end crosswise of the battery, connected to said flues and communicating with each other to permit equalization of pressures between them, each of said regenerators being provided with an individual sole channel, said channels having ports only on one side of the battery.

14. In a battery having oven chambers, heating walls contiguous to said chambers and respectively constituted of combustion flues, the combustion fines of each heating wall being communicably connected with the combustion fines of an adjacent heating wall; pillar walls directly beneath the heating walls forming the sole support for the heating walls and chambers; regenerators grouped in pairs cross wise of the battery and located between the pillar walls, each pair of regenerators being communicably-connected with combustion flues of a single heating wall, each regenerator being provided with an individual sole channel, and the sole channels of the alternate pairs of regenerators having ports on one side of the battery while the sole channels of the intermediate pairs of regenerators have ports on the opposite sides of the battery, substantially as specified.

15. A coke oven battery provided with a pluralitv of coking chambers with flued heating walls, the flues of a wall on one side of a chamber being communicably connected with those of the wall on the opposite side of said chamber; inflow and outflow regenerators communicating with the flues of said heating walls; a waste gas tunnel on one side of said battery connected to the outflow regenerators;

17. In a coke oven battery in combination: flued heating walls forming between them coking chambers, the flues of adjacent pairs of heating walls being communicably connected together and all of the flues of a given wall being adapted to pass the gases in the same direction; inflow and outflow regenerators extending across the battery and communicating with the flues of the heating walls; means whereby the inflow regenerators all simultaneously receive the gasses to be preheated from the same side of the battery, while the outflow regenerators deliver the waste gases to the opposite side of the battery; and means for reversing the flow through the regenerators and heating walls whereby the inflow regenerators become outflow regenerators and the outflow regenerators become inflow regenerators, the gases to be preheated being taken in from said opposite side of the battery and the waste gases being delivered from said first side of the battery; substantially as specified.

18. In combination with an oven chamber, fiued parallel heating walls respectively constituting the opposite side walls of said chamber, the flues of said opposite heating walls being communicably connected with each other by duct means, each flue in each of said heating walls being adapted to pass the gases simultaneously in the same direction as a flow of igases in all of the other flues in the same wa l therewith; vertical pillar walls directly beneath the heating walls and parallel therewith, said pillalr walls being the only vertical walls that are both parallel with said heating walls and directly below the oven chamber and heating walls and forming a support for the heating walls and oven cham ber; and regenerators located between the pillar walls and communicating with the flues of the heating walls substantially as specified.

19. In combination with an oven chamber, flued parallel heating walls respectively constituting the opposite side walls of said chamber, the flues of said opposite heating walls being communicably connected with each other by duct means extending over the top of the oven chamber; vertical pillar walls directly beneath the heating walls and parallel therewith, said pillar walls being the only vertical walls that are both parallel with said heating walls and directly below the oven chamber and heating walls and forming a support for the heating walls and oven chamber, and regenerators located between the pillar walls and communicating with the flues of the heating walls, substantially as specified.

In testimony whereof I have hereunto set my hand.

JOSEPH BECKER. 

